NASA SRTM Download and Formats: Elevation Tiles, Access Methods, and GIS Workflows
NASA’s Shuttle Radar Topography Mission (SRTM) is a near-global digital elevation dataset generated from radar observations collected during the Space Shuttle Endeavour mission in February 2000. The public SRTM ecosystem includes several related products, including SRTM Non-Void Filled, SRTM Void Filled, SRTM 1 Arc-Second Global, SRTMGL1, and SRTMGL3. Depending on the product, data are available at approximately 30-meter or 90-meter spacing, typically organized as one-degree geographic tiles. Common download and access routes include USGS EarthExplorer, NASA Earthdata and LP DAAC services, the USGS Global Visualization Viewer, and application-oriented services such as AppEEARS. Files and product records may use GeoTIFF, DTED, BIL, HDF-EOS, or related delivery formats. SRTM is a foundational elevation layer for terrain visualization, slope and aspect calculations, watershed modeling, visibility analysis, and geographic joins, but it represents conditions measured during the 2000 mission and should not be treated as a current terrain-monitoring service or universally complete bare-earth model.
NASA SRTM is one of the most widely used elevation resources in the GIS and geospatial ecosystem. Its importance comes from the combination of broad geographic coverage, consistent radar-derived measurements, multiple public access routes, and formats that can be used by desktop GIS, raster-processing libraries, remote-sensing platforms, and spatial databases. The phrase “NASA SRTM download” can refer to several related products rather than one single file collection, so choosing the correct product and format is the first step in a defensible workflow.
How EDK fits
For: GIS analysts, remote-sensing practitioners, cartographers, hydrologists, developers, researchers, and location-data teams that need downloadable elevation data for regional or global analysis.
SRTM is directly relevant to finding, understanding, and computing about the physical world because elevation provides geographic context for nearly every other physical feature. A road, building, stream, utility corridor, settlement, or environmental observation can be interpreted differently depending on terrain, slope, drainage position, and relative height. In a world model of Earth, SRTM can serve as an elevation surface that is joined to geographic features and used to derive measurements such as elevation summaries, slope exposure, terrain accessibility, watershed position, line-of-sight constraints, and relative relief. Its limitations also matter: because SRTM primarily reflects observations from February 2000 and may contain voids, surface artifacts, or vegetation and built structures, it should be treated as one evidence layer among many rather than as a complete or current description of every place.
- •Join SRTM elevation and derived slope values to roads, buildings, waterways, infrastructure, or public assets to compare terrain conditions across geographic features or service areas.
- •Use SRTM as a regional computation layer for terrain-aware filtering, proximity and accessibility studies, drainage screening, visibility analysis, elevation ranking, and comparisons between places where locally authoritative elevation data is unavailable.
Dataset profile
Formats
GeoTIFF
DTED
BIL with companion descriptor or header files
Product-specific NASA Earthdata packaging, including formats documented for particular SRTM collections
Access methods
USGS EarthExplorer for product search, preview, metadata, and downloads
NASA Earthdata and LP DAAC product services for SRTMGL1, SRTMGL3, and related collections
USGS Global Visualization Viewer for supported SRTM Void Filled access
AppEEARS for supported subset and application-oriented retrieval workflows
Programmatic raster processing after download using GIS, remote-sensing, or geospatial data libraries
Quality and limits
SRTM is historical and reflects the February 2000 observation period.
Some products contain voids, while void-filled products may use interpolation or external elevation sources.
Radar-derived elevation may reflect vegetation, buildings, infrastructure, or other surface features rather than bare earth.
Coverage, sampling, void treatment, and processing differ among SRTM Non-Void Filled, SRTM Void Filled, SRTM 1 Arc-Second Global, SRTMGL1, and SRTMGL3 products.
Nominal 30-meter or 90-meter spacing does not establish equivalent horizontal or vertical accuracy at every location.
Coastal, mountainous, densely vegetated, urban, snow-covered, and high-latitude areas may require additional validation.
SRTM is not a substitute for current lidar, surveyed elevation, engineering-grade terrain models, or locally authoritative datasets when those are required.
Analysis workflows
Define the area of interest and identify the exact SRTM product, version, resolution, and void treatment needed.
Download every tile intersecting the study area and preserve original files, metadata, checksums, and source identifiers.
Inspect nodata values, void masks, geographic and vertical references, tile boundaries, and units before analysis.
Mosaic tiles into a consistent raster and reproject only when required by distance, area, terrain, or modeling calculations.
Derive hillshade, slope, aspect, curvature, relief, terrain profiles, or other raster variables while retaining provenance.
Join elevation summaries or terrain derivatives to roads, buildings, streams, infrastructure, administrative areas, watersheds, or environmental observations.
Validate results against newer or higher-resolution elevation data when local accuracy, currency, safety, engineering, or regulation matters.
Record the SRTM product name, version, tile IDs, access service, download date, processing steps, and any void-filling decisions.
Value inside EDK
What NASA SRTM contains
The Shuttle Radar Topography Mission was a joint effort involving NASA, the National Geospatial-Intelligence Agency, and partner organizations. Radar interferometry from the Space Shuttle Endeavour mission was used to generate elevation data over roughly 80 percent of Earth’s land surface. The mission flew from February 11 through February 22, 2000. (usgs.gov)
The public SRTM catalog contains several product families with different processing histories and geographic coverage. USGS identifies SRTM Non-Void Filled, SRTM Void Filled, and SRTM 1 Arc-Second Global as distinct downloadable collections. The Non-Void Filled product includes processing such as water-body editing, coastline refinement, removal of spikes and wells, and filling of small voids. Void Filled products apply additional interpolation or external elevation sources to address larger missing areas. (usgs.gov)
- •SRTM 1 Arc-Second Global: approximately 30-meter spacing with global distribution, although coverage and remaining voids must be checked for the area of interest.
- •SRTMGL1.003: a 30-meter NASA/LP DAAC product listed in the MEaSUREs SRTM collection.
- •SRTMGL3.003: a 90-meter NASA/LP DAAC product suitable for analyses where broader regional coverage and smaller files are more important than the finest public SRTM spacing.
- •SRTM Water Body Data and related layers: supplementary products that can help identify water surfaces and interpret elevation tiles.
Geography, temporal coverage, and update cadence
SRTM has near-global land coverage rather than universal coverage of the entire planet. The USGS metadata for SRTM 1 Arc-Second Global identifies coverage between approximately 60 degrees north and 56 degrees south, with one-degree tiles expressed in geographic latitude and longitude coordinates. At high northern and southern latitudes, the sampling arrangement may differ from the nominal 30-meter description. (earthexplorer.usgs.gov)
The observation date is historical, not contemporary. The underlying radar mission took place in February 2000, so SRTM does not describe later roads, buildings, quarrying, landform changes, construction, erosion, or other physical changes. A product page or EarthExplorer record may show later publication or metadata-update dates, but those dates do not represent new terrain observations. (earthexplorer.usgs.gov)
- •Geographic coordinates: SRTM products are commonly distributed as geographic latitude/longitude grids referenced horizontally to WGS 84.
- •Vertical reference: USGS metadata for SRTM 1 Arc-Second Global identifies the EGM96 geoid as the vertical reference.
- •Tile structure: many products use one-degree tiles named from the tile’s lower-left coordinate, such as SRTM1N11E010V3.
- •Temporal meaning: the data is a historical elevation surface derived from the 2000 mission, not a current digital terrain-monitoring feed.
Download options and file formats
USGS EarthExplorer is a primary public route for searching, previewing, and downloading SRTM Non-Void Filled, SRTM Void Filled, and SRTM 1 Arc-Second Global products. Users generally define an area of interest, select the SRTM dataset family, inspect available tiles and metadata, and download the required files. EarthExplorer may require an account for downloads. (earthexplorer.usgs.gov)
NASA Earthdata and LP DAAC provide another access path for SRTM products, including SRTMGL1 and SRTMGL3. The exact interface and delivery endpoint depend on the collection and product version. USGS also identifies AppEEARS as an access option for free global elevation products, which can be useful when a workflow needs a spatial subset rather than a manually assembled tile archive. (earthdata.nasa.gov)
- •Desktop GIS: download GeoTIFF tiles, inspect coordinate and vertical metadata, mosaic adjacent tiles, and reproject only when the analysis requires it.
- •Command-line or Python workflows: use raster libraries to read GeoTIFF or BIL, preserve nodata values, build virtual mosaics, and derive slope, aspect, hillshade, or flow-related surfaces.
- •EarthExplorer: appropriate for product discovery, metadata review, tile selection, and direct downloads.
- •NASA Earthdata/LP DAAC and AppEEARS: useful for product-specific access, subsets, and programmatic or application-oriented workflows.
Suitable GIS workflows and interpretation cautions
A basic SRTM workflow starts by defining the study area and selecting a product whose coverage, resolution, void treatment, and format match the analysis. Download all tiles intersecting the area, verify their metadata and nodata conventions, then mosaic them into a consistent raster. Analysts should avoid silently replacing voids with zero elevation, because that can create artificial pits, cliffs, or drainage paths.
For terrain analysis, common derived products include hillshade, slope, aspect, curvature, local relief, elevation percentiles, and terrain profiles. These can be summarized by administrative areas, watersheds, road segments, building footprints, infrastructure corridors, or other geographic features. SRTM can also support screening-level watershed and visibility work, but results should be validated against higher-resolution or locally authoritative elevation data where decisions depend on engineering-grade accuracy.
- •Inspect nodata and void masks before calculating derivatives.
- •Keep the original elevation units, reference systems, and product metadata with derived outputs.
- •Use an analysis-appropriate projected coordinate system for distance, area, slope-distance, and neighborhood calculations.
- •Compare SRTM with local lidar, national DEMs, surveyed control, or newer elevation products when accuracy or currency is consequential.
- •Do not infer current building height, road grade, or flood risk solely from SRTM without checking surface-model effects and validation data.
License, strengths, and tradeoffs
NASA and USGS distribute SRTM products through public scientific-data programs, and the USGS collection pages describe open distribution for key global products. However, the exact terms, attribution expectations, disclaimers, and redistribution conditions should be checked for the specific product and access service used. The available authoritative pages do not establish one universal license statement that applies identically to every SRTM derivative, mirror, or repackaged download. (usgs.gov)
SRTM’s main strength is consistency at broad geographic scale. It gives analysts a common elevation reference that can be combined with roads, buildings, streams, land cover, administrative boundaries, imagery, and other location data. Its main tradeoff is that a globally consistent historical surface is not the same thing as a current, locally surveyed, bare-earth elevation model.
- •Strength: broad, near-global land coverage from a consistent radar mission.
- •Strength: widely supported raster formats and multiple authoritative access routes.
- •Strength: useful resolution for regional terrain, watershed, environmental, and location-based analysis.
- •Tradeoff: observations are from February 2000 and do not provide current change monitoring.
- •Tradeoff: voids, interpolation, surface features, and product-specific processing can affect local accuracy.
- •Tradeoff: 30-meter nominal spacing does not guarantee 30-meter horizontal or vertical accuracy, and it may be inadequate for parcel-scale, engineering, or detailed urban applications.
Questions teams ask
What is the best NASA SRTM format for ordinary GIS use?
GeoTIFF is usually the most convenient format because it commonly stores raster values and georeferencing in one file and is supported by major desktop GIS and raster-processing libraries. DTED and BIL are also official or commonly documented delivery formats, but they may require more explicit handling of companion metadata or format-specific conventions. Confirm the exact product’s metadata before automating ingestion.
Should I download SRTM 30-meter or 90-meter data?
Choose the product based on the analysis, not the nominal resolution alone. The approximately 30-meter products preserve more spatial detail and are generally preferable when the study area and workflow can support larger files. The approximately 90-meter products can be more efficient for broad regional or continental analysis. Neither resolution guarantees local accuracy, and both should be validated when the result affects engineering, regulation, safety, or detailed site decisions.
Is NASA SRTM updated with current elevation observations?
No. The underlying SRTM radar observations were collected during the February 2000 Space Shuttle Endeavour mission. Later publication, reprocessing, metadata, or access updates do not turn SRTM into a current elevation-monitoring service. Use newer elevation products or local authoritative surveys when terrain change matters.
Are SRTM void-filled values measured directly by the SRTM radar?
Not necessarily. USGS describes void-filled products as using interpolation and, depending on the product, other elevation sources to address missing data. A void-filled raster can be useful for continuous regional modeling, but analysts should preserve the product metadata and inspect available masks or quality information before treating every cell as an equally direct observation.
Keep exploring
nasa srtm analysis workflow
Use this related workflow page for tile selection, mosaicking, void handling, terrain derivatives, validation, and joining SRTM measurements to geographic features.
copernicus dem download and formats
Compare NASA SRTM with Copernicus DEM when choosing between historical SRTM products and newer global digital surface-model access options.
hydrosheds download and formats
Follow this page when the elevation surface is being used as the foundation for drainage grids, catchments, river networks, or watershed analysis.
Sources
USGS EROS Archive: Digital Elevation — Shuttle Radar Topography Mission (SRTM)
Authoritative overview of SRTM products, mission context, coverage, void filling, and USGS access routes.
Open sourceUSGS SRTM Data Dictionary
Documents product identifiers, tile naming conventions, resolutions, and EarthExplorer metadata fields.
Open sourceNASA Earthdata LP DAAC SRTM collection information
Lists SRTM product families such as SRTMGL1.003 and SRTMGL3.003 with their nominal spatial resolutions and mission context.
Open sourceUSGS EarthExplorer SRTM metadata record
Provides authoritative metadata for geographic reference, coverage, formats, acquisition date, and distribution.
Open sourceSRTM Collection User Guide
Explains SRTM product processing, collection structure, and the relationship between void-filled and other product versions.
Open source